The charge, q, is given by:

`q=inti\ dt`

`=int (0.3-0.2t) dt`

`=0.3t-0.1t^2+K`

At `t = 0`, `q = 0`, and this gives us `K = 0`.

So `q=0.3t-0.1t^2`

`[q]_[t=0.050]` `=0.3(0.050)-0.1(0.050)^2` `=0.015\ text[mC]`

(units are milli coulombs, as current `i` was in `"mA"`.)

Please support IntMath!